A conventional ranging apparatus to measure a distance to an object, for example, a subject includes a body, a lens attached to one end surface of the body and imaging an image of the subject, and a sensor which is attached to another end surface of the body and detects the image of the subject imaged by the lens. In assembling the conventional ranging apparatus, the sensor is first fixed through an adhesive or the like to the body, and the lens is then fixed to the body by positioning the lens and the sensor while disposing the lens to face the sensor. If necessary, after the sensor, the body and the lens are positioned, they are fixed by welding.
Because fine assembly accuracy is not required for a one-dimensional sensor such as a line sensor, it is not difficult to adjust a position between the sensor and the lens. However, in a ranging apparatus using a plurality of imaging elements (CCD sensors or MOS sensors) capable of ranging more accurately as a sensor, a more high accuracy to position between the imaging elements and a lens is requested. Consequently, a difficulty is involved in the ranging apparatus using the imaging elements when performing the positioning between the imaging elements and the lens.
In the ranging apparatus to measure a distance by use of the plurality of imaging elements, a distance is computed based on image data output from each imaging element. Therefore, if a positioning between the lens and each imaging element and between the imaging elements is not performed accurately, the accuracy of image data to measure a distance is inferior. Consequently, there is a problem that it is not possible to measure a distance accurately.
Therefore, in the ranging apparatus using the plurality of imaging elements, a high accuracy for position alignment between each imaging element as a sensor and the lens is requested, and it is necessary to enhance accuracy to attach the imaging elements and lens to the body. As a result, there is a difficulty to the positioning in the ranging apparatus using the plurality of imaging elements, compared with the conventional ranging apparatus.
To overcome the problem as mentioned above, some ranging apparatuses as shown in, for example, Japanese Patent Application Publication Nos. H10-326886, 2004-080575, and 2001-099643 have been proposed.
In a conventional ranging apparatus using a two-dimensional sensor, it is attempted to enhance accurately of a positioning of a sensor and a lens by a jig used exclusively for a assemble process. In addition, a shape of each of a substrate on which a sensor is mounted and a lens holder to which a lens is fixed has been improved to correspond to a positioning by a jig, as shown in Japanese Patent Application Publication Nos. H10-326886, and 2004-080575.
A jig is used in each of a fixed imaging apparatus as shown in Japanese Patent Application Publication No. H10-326886, and an imaging apparatus as shown in Japanese Patent Application Publication No. 2004-080575. Consequently, there are complications of preparing an exclusive jig and an assemble process. If the apparatus is assembled without using the jig in priority to working efficiency, it is not possible to improve accuracy of a positioning of a sensor and a lens.
Therefore, it is requested to provide a ranging apparatus capable of assembling easily it, improving assembly efficiency, and positioning a sensor and a lens accurately without requiring a complicate assembly process using an exclusive jig or the like.